Targeted Drug Delivery – UPSC GS3

One of the problems with medicine today is that good drugs often distribute equally into diseased and healthy cells. When drugs accumulate in healthy cells they often cause toxicity.

Scientists have identified specific receptors or markers on cancer cells and other diseased cells which distinguish them from healthy cells.

They use these markers to deliver the drug specifically to the diseased cell, thereby avoiding the collateral toxicity to the healthy cells.

The technology is based on two simple principles: find a molecule that will home in on the diseased cell and then link that to a very effective drug that will treat the disease.

So the drug piggy-backs on the homing molecule and accumulates in the diseased cell and not in the healthy cell.

The scientists take advantage of the fact that cancer cells have an enormous appetite for folic acid — which is the Trojan horse that delivers the drug. They need a lot of this vitamin for DNA synthesis.

They deliver a fluorescent dye to cancer cells using this method. This turns out to be very important because nearly 40% of all cancers tend to recur after surgery as the surgeon has failed to remove all of the malignant tissue. By helping the surgeon see the residual malignant tissue, a lot of lives can be saved.